1. Field of the Invention
This invention relates to agricultural equipment and, more particularly, to an apparatus for clearing residue from planting strips and applying an additive thereto in preparation for seeding. The invention further relates to a method of using the apparatus.
2. Background Art
There are many planting techniques currently practiced by farmers. Under most conventional processes, planting of a field is carried out in steps. First, the entire field is worked to break up the soil, break loose residue from the preceding year's crops, and break down and work the residue into the tilled soil. The planting rows in the prior year are eliminated so that the entire field has a substantially homogenous soil texture.
This conventional technique has numerous drawbacks. First of all, this technique requires the performance of multiple steps to effect planting of the field. The field is first cultivated during one or more passes of a cultivator over the field. A separate planter attachment is then utilized to deposit seed and spray fertilizer, or other additive, in an entirely separate operation. To carry out the different operations, the user is required to connect and disconnect equipment to and from a towing vehicle.
A further problem with this conventional technique is that the residue, such as corn stalks, may not be effectively pulverized, even though several passes are made over the field with the cultivator unit. The result is that the residue may jam up in the planter unit and/or block the placement of the seed and application of fertilizer.
A further problem with this conventional technique is that cultivation of the entire field increases soil erosion from both rain and wind. Not only is this undesirable from the standpoint of loosing fertile soil, but of late the federal government has imposed restrictions on erosion by requiring that a certain amount of ground cover remain in place at all times in fields.
These problems led to the development of planting techniques whereby unpulverized residue/ground cover is left in the field. The soil treatment is confined to strips in which planting takes place. Residue remains in the rows adjacent to the strips. While this type of strip treatment of soil overcomes a number of problems, such as that of erosion, it introduces complicating factors.
This planting technique complicates the application of an additive to the soil. It is common to pre-treat the field with an additive, such as anhydrous ammonia, in the fall preceding a planting season, to allow the soil to absorb the additive. Typically, the anhydrous ammonia is introduced by a delivery conduit on a fertilizer knife which penetrates several inches into the soil to release the additive beneath the soil surface. The fertilizer knife is constructed to effectively part residue in its path. However, the residue tends to wrap around the knife and progressively build up thereon. This problem is referred to in the industry as "hairpinning".
To overcome the hairpinning problem, one manufacturer uses a coulter wheel upstream of the fertilizer knife. The coulter wheel breaks up residue in the path of the fertilizer knife so that it will pass laterally to the sides of the knife.
However, even with the coulter/fertilizer knife combination, a problem still persists. The fertilizer knife creates a relatively deep slot which must be closed to retain the additive. Since anhydrous ammonia tends to vaporize rapidly, it is very important to promptly seal the slot defined by the fertilizer knife.
Heretofore, this sealing has been attempted by using a trailing pair of concave disks, which cooperate to cut the soil and develop a mound over the slot defined by the fertilizer knife. Several problems are associated with this type of closing mechanism.
First of all, the closing disks pick up residue and clumps of soil which are placed over the slot. The residue and clumps bridge the slot opening and block passage of loose soil to the bottom of the slot and thereby prevent the effective sealing thereof. As a result, the additive may evaporate off before it is absorbed in any significant amount by the soil.
Another problem with the above system is that the closing disks themselves cut a trench in the soil which trench is not effectively closed and sealed by the soil having clumps and residue therein. Even if loosened soil is deposited by the disks against the compacted trench walls, the loosened and compacted soil does not blend. The result is that, as the soil dries, cracks develop through which the additive can freely evaporate.
Due to the problems of confining additive such as anhydrous ammonia, many farmers choose to simultaneously apply the additive at the time of planting in the spring. When this is done, the concentration of the additive must be reduced. That is, an amount of additive that would be optimum for growing, if fully absorbed by the soil would bum the seed if simultaneous additive application and planting took place. Consequently, the amount of additive is significantly reduced, as a result of which a less than desirable amount of additive is absorbed by the soil. The end result is that the crop quality may be compromised.
A still further problem arises from the fact that a significantly larger volume of fertilizer is used per acre than seed. If the additive is applied and the seed planted simultaneously, the farmer is required to regularly halt operations and refill the additive supply bin. Ideally, the farmer travels continuously, without interruption, over an entire field during a planting operation.